Following a tough start to the season for both player and club, Robert Pires has insisted that Alexis Sanchez’s move to Manchester United in January was a mistake for the Chilean forward, with United’s number seven struggling for game time and goals.

Sanchez completed a move to Old Trafford in January which saw Henrikh Mkhitaryan go in the opposite direction, but it was the Chile forward’s switch which generated the greater buzz and anticipation around the Premier League.

However, ​Sanchez has fallen out of favour under Jose Mourinho this season following a troubled start to life in Manchester, and ​Arsenal legend Pires told Chilean outlet El Mercurio, via ​Manchester Evening News: “Honestly, it surprised me.

“For me, Sanchez had to stay at Arsenal, where he was one of our stars. I don’t know if he could say no to ​United, but I think the style of play of the London club suits his performances better. But you have to respect his decision.”

Sanchez became Arsenal’s most consistent source of goals under Arsene Wenger after completing his move from ​Barcelona to the Emirates in 2014, as the Chilean became the star turn of the Gunners’ attacking setup alongside Mesut Ozil.

The 29-year-old has failed to make such a mark at Old Trafford in the early phases of his Manchester United career and it appears that Sanchez has already fallen down the pecking order under Mourinho in recent weeks.

The Chilean failed to make the squad for United’s heavyweight clash with ​Juventus in the Champions League on Tuesday, three days after being named on the bench for the Red Devils’ huge Premier League showdown with ​Chelsea at Stamford Bridge.

Sanchez has scored just once for United this season, netting the dramatic late winner in Mourinho’s side’s recent comeback win over ​Newcastle United, and has not started for his side since the 0-0 draw at home to Valencia in the Champions League three weeks ago.​